Compounds for the treatment of hepatoma

ABSTRACT

Compounds of general Formula I in which the substituents of R 1  -R 7  are hydrogen, hydroxy group, C 1-6  alkyl group, C 1-6  alkoxy group, or epoxypropoxy, but at the most, six of the substituents can simultaneously be hydrogen, methoxy group, or hydroxy group, or epoxypropoxy group for activity against hepatoma. There are also described processes for the preparation of the novel compounds and useful intermediates. Substitute benzophenones are described.

This application is a Continuation-In-Part of U.S. Ser. No. 08/134,834filed Oct. 12, 1993, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a series of novel Γ-pyrone compoundswhich are active in the treatment of hepatoma, to processes for theirpreparation and to certain useful intermediates for the same processes.

BACKGROUND OF THE INVENTION

Based on the fact that the human body is susceptible to cancer, severalmethods to decrease or eliminate the painful illness, or to discovercytotoxic substances have been proposed.

Although many chemotherapeutic agents are clinically useful for thetreatment of several forms of cancer such as acute leukemia, Burkitt'slymphoma, retinoblastoma, Ewing's sarcoma, testicular carcinoma,choriocarcinoma, Hodgkin's disease, lymphosarcoma, rhabdomyosarcoma, ormycosis fungoides, they are inactive against human hepatoma.

Some natural Γ-pyrone compounds, Psorospermin (1) and related compounds,3',4'-deoxy-psorospermin, 3',4'=deoxypsorospermin-3',4'-diol,3',4'-deoxy-4'-chloropsorspermin-3'-ol, O⁵-methyl-3',4'-deoxypsorospermin-3'-ol exhibit strong cytotoxic effectsagainst leukemia cells (Habib, A. M. et al., 1987, J. Org. Chem. 52,412-18). Recently Cushman, M. et al., reported the cytotoxicities ofΓ-pyrone compounds, flavonoid analogues (J. Nat. Prod., 54, 1656-60,1991). The inventors have also discovered more potent and selectiveantitumor agents, which are Γ-pyrone compound, cyclomorusin(2),cycloartomunin (3), dihydrocyclo-artomunin(4), artomunoxanth-otrioneepoxide(7), dihydroisocycloartomunin(5), artomunoxanthone(6),cyclocommunol(8), cyclo-mulberrin(9), cyclocommunin(10) which wereisolated and identified from the root bark of Formosan tripterospermumplants (Lin, C. N. et al., 1991, Phytochemistry, 30, 1669-1671; ibid,1992, 31,364-67, 2563-64, 2922-24), and have exhibited cytotoxic effectsagainst human hepatoma PLC/PRF/5 and KB cells in vitro. The namePLC/PRF/5 designates human primary liver cancer cells; the symbol KBdesignates epidermoid carcinoma cells.

SUMMARY OF THE INVENTION

The compounds of this invention have the general formula (I): ##STR1##in which the substituents of R₁ -R₇ are hydrogen, hydroxy group, C₁₋₆alkyl group, C₁₋₆ alkoxy group, or epoxypropoxy, but at the most, six ofthe substituents can simultaneously be hydrogen, methoxy group, orhydroxy group, or epoxypropoxy group.

The invention also covers compounds of formula II: ##STR2## in which thesubstituents of R₁ -R₉ are hydrogen, hydroxy group, C₁₋₆ alkyl group,C₁₋₆ alkoxy group, or epoxypropoxy group, but at the most, seven of thesubstituents are simultaneously hydrogen, methoxy group, hydroxy group,or epoxypropoxy group.

The compounds of formula (II) in which the substituents of R₈, R₉ arehydrogen, hydroxy group, or epoxypropoxy group, are preferred.

The synthesized compounds in this invention include xanthones of formulaI and benzophenones of Formula II which are structurally related to theflavonoids.

The invention also covers methods of preparation of the above mentionedcompounds.

A method of preparing compounds with the structure according to formulaI, includes reacting a compound of formula III with a benzene, whereinthe substituents of R₅ -R₇, R₉ have the meaning defined above to obtaina compound of formula II and cyclizing the compound of formula IIwherein the substituents of R₁ -R₉, have the meaning defined above.

Further, a compound of formula I may be reacted with a phenol compoundand hydrogen iodide wherein the substituents of R₁ -R₇, can be hydroxygroup to hydrolyze the alkoxy groups.

The reaction schemes are shown hereinbelow: ##STR3##

Tables 1 and 2 summarize some of the compounds of formula I and theirproperties.

                                      TABLE 1                                     __________________________________________________________________________     ##STR4##                                                                                                                         ED.sub.50 (μg/ml)      example                                                                           compound                                                                           R.sup.1                                                                           R.sup.2 R.sup.3 R.sup.4                                                                           R.sup.5 R.sup.6 R.sup.7                                                                          KB   PLC/PRF/5            __________________________________________________________________________    11  11   OH  H       OH      H   H       OH      OH NS   NS                   14       H   H       OH      OH  H       OH      OH NS   NS                   2   13   H   H       OH      H   H       H       H  0.77 3.75                 3   14   H   H                                                                                      ##STR5##                                                                             H   H       H       H  0.85 1.43                 4   15   OH  H       H       H   H                                                                                      ##STR6##                                                                             H  NS   NS                   5   16   H                                                                                  ##STR7##                                                                             H       H   H                                                                                      ##STR8##                                                                             H   0.0043                                                                            0.23                 25       H   H                                                                                      ##STR9##                                                                             H   H                                                                                      ##STR10##                                                                            H  0.11 0.24                 8   21   OH  H                                                                                      ##STR11##                                                                            H                                                                                  ##STR12##                                                                            H       H   0.089                                                                              0.061               Cisplatin                                           0.16 5.29                 __________________________________________________________________________     ##STR13##                                                                     NS no dignificant activity                                               

                                      TABLE 2                                     __________________________________________________________________________     ##STR14##                                                                                                                         chemical                 example                                                                           compound                                                                           R.sup.1                                                                           R.sup.2 R.sup.3 R.sup.4                                                                           R.sup.5 R.sup.6 R.sup.7                                                                           formula                                                                            mp                  __________________________________________________________________________                                                              (°C.)        11  11   OH  H       OH      H   H       OH      OH  C.sub.17 H.sub.16                                                             O.sub.6                                                                            >300                14       H   H       OH      OH  H       OH      OH  C.sub.17 H.sub.16                                                             O.sub.6                                                                            >300                2   13   H   H       OH      H   H       H       H   C.sub.13 H.sub.8                                                              O.sub.3                                                                            241˜242       3   14   H   H                                                                                      ##STR15##                                                                            H   H       H       H   C.sub.16 H.sub.12                                                             O.sub.4                                                                            157˜158       4   15   OH  H       H       H   H                                                                                      ##STR16##                                                                            H   C.sub.16 H.sub.12                                                             O.sub.5                                                                            153˜154       5   16   H                                                                                  ##STR17##                                                                            H       H   H                                                                                      ##STR18##                                                                            H   C.sub.19 H.sub.16                                                             O.sub.6                                                                            170˜171       25       H   H                                                                                      ##STR19##                                                                            H   H                                                                                      ##STR20##                                                                            H   C.sub.19 H.sub.16                                                             O.sub.6                                                                            187˜188       8   21   OH  H                                                                                      ##STR21##                                                                            H                                                                                  ##STR22##                                                                            H       H   C.sub.19 H.sub.16                                                             O.sub.7                                                                            180˜182       __________________________________________________________________________

As shown in the above reaction schemes, a benzoyl chloride is reactedwith a benzene by Friedel-crafts acylation to yield a benzophenoneprecursor, and then cyclization is carried out to yield a xanthone.Various epoxyproxy derivatives of xanthones of formula I can be producedby reaction in an alkaline aqueous solution with epichlorohydrin inexcess amount. Methoxybenzoylchloride was obtained frommonomethoxylbenzoic acid as the starting material, then reacted withdimethoxybenzene yielding a tri-methoxyxanthone. Based on this method2,3-dimethoxylbenzoic acid as the starting material, yielded abenzophenone of formula II as the intermediate which then yielded thexanthone compound (I). In the intermediates benzophenone of formula IIthe substituents of R8 and R9 may be hydrogen, methoxy, R1-R7 may behydrogen, hydroxy, C₁₋₆ alkyl, C₁₋₆ alkoxy group, or epoxypropoxy group.This synthetic method also includes preparation of the benzophenonecompounds, the latter may be reacted with tetramethylammonium hydroxide,to yield xanthone compounds in which the substituents may be hydroxy,methoxy, or epoxyproxy which obtained from reaction of thehydroxyxanthone with epichlorohydrin.

The, purified compounds were identified by UV, IR, ¹ H-NMR, ¹³ C-NMR,EIMS and physical properties.

PLC/PRF/5 cells were isolated from human hepatoma and are known toproduce HBs Ag continuously in culture fluids. The cells were grown ascontinuous cultures in a growth medium consisting of Dulbecco's modifiedEagle medium (DMEM, GIBCO, Grand Island, N.Y.), 10% fetal bovin serum(FBS, GIBCO), 100 IU/ml penicillin, 100 g/ml streptomycin and 2 mML-glutamtne. The KB cells were maintained on DMEM containing 10% FBSL-glutamine and antibiotics. For the microassay, the growth medium wassupplemented further with 10 mM Hepes buffer, pH 7.3.

The microassay for anticellular effect was performed as described in Ito(1984) J. Interferon Res. 4,604,608.The ED₅₀ values were calculated froma semilog plot of the drug concentration vs. the percentage of viablecells on day 4.

The results are listed in Table 1 and Table 2 and show chemical data andcytotoxicity (ED50 values in μg/ml⁻¹) of Γ-pyrones; d=equals nosignificant activity. For significant activity of the pure compound, anED50 less than 4.0 μg/ml⁻¹ is required; N=8. A=2,3-epoxy propoxy.

Although compound 13 showed significant and potent inhibitory activityagainst human hepatoma PLC/PRF/5 and KB cells in vitro, the ED₅₀ valuesare 3.73 μg/ml and 0.77 μg/ml. Compound 14 was epoxidized from 13, isenhanced very markedly the inhibitory effects against human hepatomaPLC/PRF/5 cells in vitro. The epoxidation took place at 2,6-OH, 3,6-OHof formula I, and showed significant inhibitory effect against humanhepatoma PLC/PRF/5 and KB cells in vitro. The compound2,6-di(2,3-epoxypropoxy) xanthone component (16) showed more potentinhibitory activity against KB cells in vitro, the ED₅₀ values were over40 times that of cisplatin. On the other hand, the compounds 21epoxidized from 1,3,5-tri-hydroxy-xanthone, showed significant novelinhibitory activity against human hepatoma PLC/PRF/5 and KB cells invitro. Based on the above results, it is clearly indicated that thecompounds of this invention having an additional epoxide groupsubstituents in the xanthone or benzophenone structure show novelinhibitory activity.

The novel two types of compounds Γ-pyrone, together with a conventionaladjuvant, carrier, or diluent, may be placed into the form ofpharmaceutical compositions and unit dosages thereof. In such forms,they may be employed as solids or liquids for oral use; in the form ofsuppositories for rectal administration; in the form of sterileinjectable solutions for parenteral (including subcutaneous) use. Thesolid pharmaceutical dosages may comprise disintegrating agents such asstarch, sodium carboxymethyl-cellulose, and/or binders such as ethylalcohol, glycerin, and/or carriers such as magnesium stearate, lactose,which are prepared by conventional pharmaceutical methods. The sterileinjectable solution preparations can be adjusted with buffers, such asphosphates, if desired, with auxiliary agents, and emulsifiers.

The novel pharmaceutical compositions in unit dose form are very usefulin the treatment of hepatoma. The novel compounds of the invention mayaccordingly be administered to a living subject, including a human, andshould be adjusted according to the complexity of the symptoms. Thepreferred individual dosage is 50 to 300 mgs for oral administration and2 to 15 mgs for intravenous administration and can be administered up to3 times daily.

A typical tablet which may be prepared by conventional tablettingtechniques contains:

    ______________________________________                                        active compound  40 mg                                                        lactose          30 mg                                                        starch            8 mg                                                        magnesium stearate                                                                             10 mg                                                        corn starch      12 mg                                                                         100 mg                                                       ______________________________________                                    

EXAMPLE 1 Preparation of2-Hydroxy-4,6-dimethoxy-2',3'-dimethoxybenzophenone (18 a) and2,4,6-trimethoxy-2'-hydroxy-3'-methoxybenzophenone (18 b)

2,3-dimethoxybenzoic acid (1.8 g, 9.89 m mol) in dry C₆ H₆ (25 ml) wastreated with 3.5 ml of oxalyl chloride under an argon atmosphere andthrough stirring at room temperature.

After 5 hrs the solvent and the excess reagent were removed underreduced pressure. The residue, 2,3-dimethoxybenzoyl chloride wasdissolved in anhydrous Et₂ O (40 ml) and 1,3,5-trimethoxybenzene (1.6 g,9.52 mmol) and AlCl₃ (4.0 g) were added. After stirring 15 hrs at roomtemperature, the mixture was hydrolyzed with ice-H₂ O (300 mL)containing concentrated HCl (35 mL), and extracted with CH₂ Cl₂. Solventremoval gave a crude product that was purified by column chromatography(silica gel-CH₂ Cl₂) to yield pale yellow oil (MeOH)(18),2.9 g (9.5mmol, 92%) The product is a mixture of the two compounds 18a and 18b.

¹ H-NMR (CDCl₃): δ 3.70 (12H, s, 4 OMe), 3.86 (6H, s, 2 OMe), 3.91 (6H,s, 2 OMe), 6.16 (4H, s, H-3 and H-5 of 18a and 18b), 6.72 (2H, t, J=8.0,H-4' of 18a and 18b), 6.91-7.06 (4H, m, H-5' and H-6' of 18a and 18b),12.51 (2H, s, 2 OH of 18a and 18b, D₂ O exchangeable).

EXAMPLE 2 Preparation of 3-hydroxyxanthone (13)

1.6 g(7.08 mmol) of methoxyxanthone was refluxed at 160° C. in a mixtureof hydrogen Iodide (35 ml) and phenol (42 ml) for 8 hours. The resultingmixture was then poured into NaHSO₃ aqueous solution and generated ayellow precipitate.

The precipitate was collected and purified with a silica gel column bychromatography (Eluted with chloroform-methanol, 4:1). 1.40 g (6.60mmol) of 3-hydroxyxanthone, a yellow needles, were crystallized frommethanol. The yield was 93%. The data of the physical properties arelisted below.

mp:241°-242° C. MS (m/z, %): 212 (100) (M⁺); UV λ max (MeOH) nm (log ε):235 (4.06),265 (3.39),330 (3.59); λmax (MeOH+NaOAc) nm (log ε): 230,265(sh), 335; IR (KBr): 3115, 1615 cm⁻¹ 1 H-NMR (DMSO): see Table 3 Anal.(C₁₃ H₈ O₃) C, H.

EXAMPLE 3 Preparation of 3-(2,3-Epoxypropoxy) xanthone (14)

To a solution of 0.19 g(4.71 m mol) of sodium hydroxide in 6.18 ml. ofisopropanol and 1.3 ml of water, 1.00 g (4.72 mmol) of 3-hydroxyxanthone(5H) and 3.76 ml (46.86 mmol) of epichlorohydrin were added. Thecomponents were reacted under stirring at 70° C. for 2 hours. Theresulting mixture was filtered to remove a dimer side product a glycidylether. The filtrate was concentrated at reduced pressure at 50°˜60° C.and 10 ml of isopropanol was added to the mixture to yield more of thedimer which was filtered Off from hot mixture. The clear filtrate wasallowed to cool, and the thus formed solid was then washed with 1.40 mlof isopropanol and dried in air to give 945 mg (4.46 mmol) of brownproduct. The yield was 74%. Purified by chromatography on silica gel andcrystallized from dichloromethane, a colorless powder of3-(2,3-epoxypropoxy)xanthone was obtained. The data of physicalproperties are listed below.

mp: 157°-158° C.; MS (m/z)%: 268 (100) (M⁺); IR (KBr): 1645, 1265 cm⁻¹ ;¹ H-NMR (CDCl₃): δ 2.79-2.99 (m, CH₂ of epoxy ring), 3.42 (m, 1H, CH ofepoxy ring), 4.05 (dd, J=11, 6.0 Hz, 1H), 4.39 (dd, J=11, 3.0 Hz, 1H),6.91 (d, J=2.4 Hz, 1H, H-4), 6.95 (dd, J=9.0, 2.4Hz, 1H, H-2), 7.27-7.47(m, 2H, H-6 and H-7), 7.65-7.70 (m, 1H, H-5), 8.26 (d, J=9.0 Hz, 1H,H-1), 8.32 (dd, J=9.0, 1.5 Hz, 1H, H-8); ¹³ C-NMR (CDCl₃) δ 44.5 (CH₂ ofepoxy ring), 69.2 (OCH₂), 49.7 (CH of epoxy ring), 101.1 (C-4),113.4(C-2), 116.2 (C-8b), 117.7 (C-5), 121.9 (C-8a), 123.9 (C-7), 126.6(C-8), 128.4 (C-1), 134.3 (C-6), 156.2 (C-4b), 157.9 (C-4a), 163.7(C-3), 176.2 (CO); Anal: (C₁₆ H₁₂ O₄) C,H.

EXAMPLE 4 Preparation of 6-(2,3-Epoxypropoxy)-1-Hydroxyxanthone (15)

To a solution of 0.42 g (10.5 m mol) of sodium hydroxide in 3 ml ofwater was added 50 ml of 2-propanol and the 1.2 g (5.26 mmol) of1,6-dihydroxyxanthone. To the above mixture was then added 10 ml (124.63mmol) of epichlorohydrin, and the mixture was heated at 70° C. for 3 hrswith stirring.

The hot reaction mixture was filtered to remove the dimeric byproductthe glycidyl ether. The filtrate was concentrated under reduced pressureat 50° to 60° C. The semisolid residue was treated with 20 ml ofrefluxing 2-propanol and more of the dimer was filtered off from the hotmixture. The clear filtrate, on cooling, yielded a solid. This wascollected, washed with 3 ml of 2-propanol, air-dried and yielded atan-colored product. It was purified by column chromatography (silicagel-CH₂ Cl₂) and crystallized from CH₂ Cl₂ to give yellow powder(15),1.4 g (4.93 mmol, 94%).

MS (m/z)%: 284 (100) (M⁺); IR (KBr): 3450, 1650, 1630 cm⁻¹ 1 H-NMR(CDCl₃): δ 2.81 (1H, dd,. J=11, 6.0 Hz, CH₂ in the epoxide ring), 2.91(1H, t, J=5 Hz, CH₂ in the epoxide ring), 3.42 (1H, m, CH in the epoxidering), 4.04 (1H, dd, J=11, 6.0 Hz, OCHH), 4.43 (1H, dd, J=11, 3.0 Hz,OCHH), 6.78 (dd, J=9.0 Hz, 1.0 Hz, 1H, H-2), 6.88 (2H, m, H-4, H-5),6.97 (1H, dd, J=9.0, 2.5 Hz, H-7), 7.55 (1H, t, J=9.0 Hz, H-3), 8.16(1H, d, J=9.0 Hz, H-8), 12.75 (1H, s, 1-OH, exchange with D₂ O);(Wu,E.S.C. et al 1989); ¹³ C-NMR (CDCl₃): δ 44.5 (CH₂ in the epoxidering), 49.7 (CH in the epoxide ring), 69.4 (OCH₂), 100.9 (C-5) 106.8(C-4), 108.4 (C-8b), 110.2 (C-2 113.7 (C-7), 114.7 (C-8a), 127.6 (C-8)136.2 (C-3), 156.3 (C-4a), 158.0 (C-4b) 161.9 (C-1), 164.4 (C-6), 181.3(CO); Anal. (C₁₆ H₁₂ O₅) C. H

EXAMPLE 5 Preparation of 2, 6-di (2,3-epoxypropoxy) xanthone (16)

To a solution of 0.42 g (10.5 m mol) of sodium hydroxide in 3 ml of2,6-dihydroxyxanthone. To the above mixture was then added 10 ml (124.63mmol) of epichlorhydrin, and the mixture was treated as in example 3 toyield a colorless powder (16), 1.2 g (3.85 mmol, 73%).

MS (m/z)%: 340 (100) (M⁺); IR (KBr): 1655, 1620 cm⁻¹ ; ¹ H-NMR (CDCl₃) δ2.81 (2H, m, CH₂ in the epoxide ring), 2.96 (2H, dd, J=10, 4.5 Hz, CH₂in the epoxide ring), 3.42 (2H, M, 2xCH in the epoxide ring), 4.01 (1H,dd, J=11, 6.0 Hz, OCHH), 4.05 (1H, dd, J=11, 6.0 Hz, OCHH), 4.38 (1H, t,J=3 Hz, OCHH), 4.43 (1H, t, J=3 Hz, OCHH), 6.91 (1H, d, J=2.5 Hz, H-5),6.97 (1H, dd, J=9.0, 2.5 Hz, H-3), 7.35 (1H, dd, J=9.0, 2.5 Hz, H-7),7.41 (1H, d, J=9.0 Hz, H-4), 7.68(1H, d, J=2.5 Hz, H-1), 8.26 (1H, dd,J=9.0 Hz, H-8), (Wu,E.S.C. et al 1989); ¹³ C-NMR (CDCl₃): δ 44.5, 44.6(CH₂ in the epoxide ring), 49.8, 50.0 (CH in the epoxide ring), 69.3,69.4 (OCH₂), 100.9 (C-5), 106.9 (C-1), 113.5 (C-7), 115.6 (C-8a), 119.3(C-4), 122.2 (C-8b), 124.6 (C-3), 128.3 (C-S), 151.2 (C-4a), 154.8(C-2), 157.8 (C-4b), 163.7 (C-5), 176.0 (CO). Anal. (C₁₉ H₁₆ O₆) C, H

EXAMPLE 6 Preparation of 1,3,5-trimethoxyxanthone (19)

The mixture of the compounds 18a and 18b (2.9 g, 9.15 mmol) from Example1 was treated with pyridine (52.8 ml), H₂ O (26.4 mL) and aqueous 10%tetramethytarmuonium hydroxide (18 mL). The mixture was refluxed 34 hrs,poured into ice, acidified with HCl, and extracted with Et₂ O, yieldingan oil which, after purification by column chromatography(silica gel-CH₂Cl₂) and crystallized from CH₂ Cl₂ yielded colorless powder (19), 2.03 g(7.10 mmol, 78%).

mp: 233°-235° C.; ¹ H-NMR (CDCl₃): δ 3.89, 3.96, 4.00 (3s, 9H, 3 Ome),6.34 (1H, d, J=2.5 Hz, H-2), 6.62 (1H, d, J=2.5 Hz, H-4), 7.13-7.28 (2H,m, H-6 and H-7), 7.86 (1H, dd, J=9.0,1.5 Hz, H-8),

EXAMPLE 7 Preparation of 1,3,5-trihydroxyxanthone(20)

A mixture of compound 19 (1.9 g, 6.64 mmol) phenol ml) and HI (35 ml)was refluxed at 160° C. for 8 hour and the reaction mixture was pouredinto aqueous NaHSO₃ solution. The resulting yellow precipitate, wascollected, purified by silica gel column chromatography (CH₂ Cl₂ -MeOH,4:1), and crystallized from methanol to give pale yellow needles 20,1.41 g (5.78 mmol, 87%).

mp: 211°-213° C.; ¹ H-NMR, CDCl₃): δ 6.19 (1H, d, J=2.0 Hz, H-2), 6.39(1H, d, J=2.0 Hz, H-4), 7.07-7.19 (2H, m, H-6 and H-7), 7.62 (1H, dd,J=9.0,2.5 Hz. H-8).

EXAMPLE 8 Preparation of 3,5-di (2,3-epoxypropoxy)-1-hydroxyxanthone(21)

To a solution of 0.28 g (5.0 m mol) of potassium hydroxide in 3 ml ofwater was added 25 ml of 2-propanol and the 1.3 g (5.33 m mol) of1,3,5-trihydroxyxanthone. To the above mixture was the added 7.5 ml(93.47 m mol) of epichlorohydrin, and the mixture was treated as example4 to yield a pale yellow powder (MeOH) (21), 0.45 g (1.26 mmol, 35%)

MS(m/z)%:356 (100) (M⁺); IR(KBr) :3500,1670, 1620 (cm⁻¹); ¹ H-NMR(CDCl₃): δ 1.61-2.78 (2H, m, CH₂ in the epoxide ring), 2.94-3.01 (2H, m,CH₂ in the epoxide ring), 3.41 (1H, m, CH in the epoxide ring), 3.50(1H, m, CH in the epoxide ring), 4.03 (1H, dd, J=11,6.0 Hz, OCHH), 4.11(1H, dd, J=11, 6.0 Hz, OCHH), 4.35 (1H, dd, J=11 3.0 Hz, OCHH), 4.48(1H, dd, J=11 3.0 Hz, OCHH), 6.38 (1H, d, J=2.5 Hz, H-2), 6.57 (1H, d,J=2.5 Hz, H-4), 7.30 (2H, m, H-6 and H-7), 7.85 (1H, dd, J=9.0, 2.5 Hz,H-8) (Wu,E.S.C. et al 1989); ¹³ C-NMR (CDCl₃): δ 44.6 (2 CH₂ in theepoxide ring), 49.7 and 50.1 (2 CH in the epoxide ring), 69.2 and 70.6(20CH₂ ), 93.5 (C-4), 97.9 (C-2), 104.2 (C-8b), 117.7 (C-8), 118.0(C-6), 122.0 (C-8a), 123.6 (C-7), 147.2 (C-4b and C-5), 157.5 (C-4a),163.4 (C-1), 165.4 (C-3), 180.8 (CO); Anal: Anal. (C₁₉ H₁₆ O₇) C, H

EXAMPLE 9 Preparation of 3,6-di(2,3-epoxypropxy)xanthone(17)

To a solution of 0.42 g (10.5 mmol) sodium hydroxide in 3 mL water wasadded 50 mL 2-propanol and then 1.2 g (5.26 mmol) of3,6-dihydroxyanthone. To the above mixture was then added 10 mL (124.63mmol) of epichlorohydrin, and the mixture was treated as for 15 to yielda colourless powder (CH₂ Cl₂)(17), 1.4 g(4.49 mmol, 85%); MS, m/z (%)

340 (100) (M⁺); IR (KBr) 1650, 1620 cm⁻¹ ; ¹ H NMR (CDCl₃): δ 2.81 (2 H,dd, J=4.8, 2.5 Hz, CH₂ in the epoxide ring), 2.97 (2 H, t, J =4.8 Hz,CH₂ in the epoxide ring), 3.42 (2 H, m, 2 x CH in the epoxide ring),4.05 (2H, dd, J =11, 6.0 Hz, 2 x OCHH), 4.39 (2H, dd, J =11, 3.0 Hz, 2 xOCHH), 6.89 (2 H, d, J=2.5 Hz, H-4 and H-5), 6.97 (2H, dd, J=9.0, 2.5Hz, H-2 and H-7), 8.24 (2H, d, J =9.0 Hz, H-1 and H-8 (Wu et al 1989);¹³ C NMR (CDCl₃): δ 44.6 (2CH₂ in the epoxide ring), 49.8 (2CH in theepoxide ring), 69.3 (2OCH₂), 101.2 (C-4 and C-5), 113.1 (C-2 and C-7),116°-2 (C-8a and C-8b), 128.3 (C-1 and C-8), 157.9 (C-4a and C-4b),163.4 (C-3 and C-6), 175.4 (CO) (Chaudhuri et al 1978; Frahm & Chaudhuri1979; Biemann 1989); Anal (C₁₉ H₁₆ O₆) C, H.

2-Hydroxy-4-methoxy-2'-methoxybenzophenone, 4a2,4-dimethoxy-2'-hydroxybenzophenone, 4b

To a solution of 2.0 g (13.14 mmol) of 2-methoxybenzoic acid in 60 ml ofdry benzene, 5 ml oxalyl chloride was added under stirring at roomtemperature. After 2 hours, solvent and excess reagents were removed atreduced pressure. The residual 2-methoxybenzoyl chloride was dissolvedin 80 ml of anhydrous ether, and then 1.8 g (13.03 mmol) of1,3-dimethoxybenzene and 5.0 g of aluminum chloride were added. Afterstirred at room temperature for 8 hours, the resulting mixture washydrolyzed by 500 ml of ice water containing 45 ml of concentrated HCland then extracted with chloroform. The solvent was removed to give acrude product. After purified by column chromatography, 2.20 g (8.53mmol) of a yellow oily product was obtained and the yield was 65%. Thedata of the physical properties of the compounds were measured and arelisted below. The product was a mixture of the compounds 4a and 4b.

¹ H NMR (CDCl₃): δ 3.76, 3.82 (2s, 12H), 6.33 (dd, J=8.5, 2.4Hz, 2H),6.47 (d, J=2.4Hz, 2H), 7.01 (m, 4H, aromatic H), 7.24 (m, 4H, aromaticH), 7.42 (m, 2H, aromatic H), 12.72 (s, 2H).

According to the method of production of2-hydroxy-4-methoxy-2'-methoxybenzphenone (4a) and 2,4-dimethoxy-2'-hydroxybenzophenone (4b), 2.00 g 13.14 mmol) of2-methoxybenzoic acid was reacted with 2.19 g (13.04 mmol) of1,3,5-trimethoxy benzene to give 2.20 g (7.75 mmol) of 3,4-dimethoxy-2-hydroxy-2'-methoxybenzophenone and2,3,4-trimethoxy-2'-hydroxybenzophenone Then, described in example 3,1.35 g (5.92 m mol) of 3,4-dihydroxybenzophenone as pale yellow powderwas produced. The physical properties were measured and are listedbelow.

mp: 238°-240° C.: MS (m/z) %: 228 (100) (M⁺); UV λmax (MeOH)nm(logε):207(3.80), 237(4.18), 255(4.08), 285 (sh) (3.49), 315 (3.74); λmax(MeOH+NaOAc+H₃ BO₃)nm(logε) 208, 235, 265, 285(sh), 320; IR (KBr): 3200,1640 cm⁻¹ ; ¹ H-NMR(CDCl₃): δ 6.94 (1H, d, J=8.5 Hz, H-2), 7.41-7.4 6(1H, m, H-7), 7.57 (1H, d, J=8.5 Hz, H-1), 7.63 (1H, m, H-6), 7.80-7.86(1H, m, H-5), 8.15 (1H, dd, J=8.5, 1.5 Hz, H-8) Anal. (C₁₃ H₈ O₄) C, H.

Based on the examples described above, the following compounds areproduced.

    ______________________________________                                        tripteroside     R.sub.1 = R.sub.3 = R.sub.7 = OH, R.sub.6 = O--GLU.          norathyrol       R.sub.1 = R.sub.3 = R.sub.6 = R.sub.7 = OH,                  1,3-Dihydroxyxanthone                                                                          R.sub.1 =R.sub.3 =OH                                         1,3,6,7-tetrahydroxy                                                                           R.sub.1 =R.sub.3 =R.sub.6 =R.sub.7 =OH                       xanthone                                                                      2 3-Dimethoxyxanthone                                                                          R.sub.1 =R.sub.3 =OCH.sub.3                                  2,3-Dihydroxyxanthone                                                                          R.sub.2 =R.sub.3 =OH                                         3,4,6,7-tetrahydroxy                                                                           R.sub.3 =R.sub.4 =R.sub.6 =R.sub.7 =OH                       xanthone)                                                                     3,4-Dimethoxyxanthone                                                                          R.sub.3 =R.sub.4 =OCH.sub.3                                  1,6-Dimethoxyxanthone                                                                          R.sub.1 =R.sub.6 =OCH.sub.3                                  3,5-Dimethoxyxanthone                                                                          R.sub.3 =R.sub.5 =OCH.sub.3                                  3,5-Dihydroxyxanthone                                                                          R.sub.3 =R.sub.5 =OH                                         2,6-Dimethoxyxanthone                                                                          R.sub.2 =R.sub.6 =OCH.sub.3                                  1,6-Dimethoxyxanthone                                                                          R.sub.1 =R.sub.6 =OCH.sub.3                                  1,6-Dihydroxyxanthone                                                                          R.sub.2 =R.sub.6 =OH                                         3,6-Dimethoxyxanthone                                                                          R.sub.3 =R.sub.6 =OCH.sub.3                                  2,6-Dimethoxyxanthone                                                                          R.sub.2 =R.sub.6 =OCH.sub.3                                  2,6-Dihydroxyxanthone                                                                          R.sub.2 =R.sub.6 =OH                                         3,6-di(2,3-epoxypropoxy)                                                                       R.sub.3 =R.sub.6 =epoxypropoxy                               xanthone                                                                      3,6-Dimethoxyxanthone                                                                          R.sub.3 =R.sub.6 =OCH.sub.3                                  3,6-Dihydroxyxanthone                                                                          R.sub.3 =R.sub.6 =OH                                         ______________________________________                                    

Formula(2)

28 4,6-Dimethoxy-2-hydroxy-2'-methoxybenzophenone

29 2,4,6-trimethoxy-2'-hydroxybenzophenone

30 4,5-Dimethoxy-2-hydroxy-2'-methoxybenzophenone

31 2,4,5-trimethoxy-2'-hydroxybenzophenone

32 3,4-Dimethoxy-2-hydroxy-2'-methoxybenzophenone

33 2,3,4-trimethoxy-2'-hydroxybenzophenone

34 2-Hydroxy-4-methoxy-2',3'-dimethoxybenzophenone

35 2,4-dimethoxy-2'-hydroxy-3'-methoxybenzophenone

36 2-Hydroxy-6-methoxy-2',4'-dimethoxybenzophenone

37 2,6-dimethoxy-2'-hydroxy-4'-methoxybenzophenone

38 2-Hydroxy-5-methoxy-2',4'-dimethoxybenzophenone

39 2,5-dimethoxy-2'-hydroxy-4'-methoxybenzophenone

40 2-Hydroxy-4-methoxy-2',4'-dimethoxybenzophenone

41 2,4-dimethoxy-2'-hydroxy-4'-methoxybenzophenone

42 3,4-Dimethoxy-2-hydroxy-2',4',5'-trimethoxybenzophenone

43 2,3,4-trimethoxy-2'-hydroxy-4',5'-dimethoxybenzophenone

The activity of compounds 16, 17 and 21 on macromolecular synthesis weredetermined by measuring the isotopic incorporation of ³ H!-thymidine,-uridine and -methionine in the human PLC/PRF/5 and KB cellsrespectively.

PLC/PRF/5 cells were obtained from human hepatoma and are known toproduce HBs Ag continuously in culture fluids. Human hepatoma PLC/PRF/5and epidermis carcinoma KB cells were maintained in Dulbeceo's modifiedEagle medium (DMEM, Gibco BRL Grand Island, N.Y., U.S.A.), containing10% fetal bovine serum (FBS, Gibco BRL), 2 mM L- glutamine, 100 unitsmL-1 penicillin, 100 μg mL-1 streptomycin. The 212 cells were maintainedin Minimum essential alpha medium (MEM, Gibco BRL), containing 10% calfserum (Gibco BRL). For microassay, the growth medium was supplementedwith 10 mM HEPES buffer, pH 7.3 and incubated at 37° C. in a CO₂incubation.

Inhibition of Macromolecular Synthesis. The synthesis of macromoleculeswere measured by the incorporation of ³ H-thymidine, -uridine or-methionine (New England) Nuclear, Boston, Mass., USA) into the tumorcells. Briefly, the tumor cell (11.5×10⁴ /100 μl/well) maintained ingrowth medium with or without drugs in microplates were incubated at 37°C. The cells after pulsed labeling with ³ H!-thymidine, -uridine, or-methionine for 18 hrs at day 4 post-treatment were harvested and loadedonto glass filter paper (Skatron. Va., USA). The incorporationactivities of the cells were measured by the liquid scintillationcounter (LS-5000 TA, Beckman Calif., USA). All treatments were conductedin quadruplicate and the mean values were used for analysis. Eachexperiment was repeated at least 3 times. The data shown are mean countsper minute (CPM)±SEM. Percent inhibition of ³ H!-thymidine, -uridine, or-methionine incorporation was calculated as follows: ##EQU1##

The invention is illustrated by FIGS. 1-6 of which;

FIGS. 1 and 2 illustrate the activity of compound No. 16, which is2,6-di(2,3-epoxypropoxy)xanthone;

FIGS. 3 and 4 illustrate the activity of compound No. 17, which is3,4-Dihydroxyxanthone;

FIGS. 5 and 6 illustrate the activity of compound No. 21, which is3,5-di(2,3-epoxypropoxy)-1-hydroxyxanthone.

FIGS. 1, 3 and 5, indicate the time-dependent effects of compounds 16,17 and 21 on DNA, RNA and protein synthesis in the human PLC/PRF/5 cellsand show that effects are significant at low concentration but theeffects in KB cells are not apparent. The figures show that theinhibition of macromolecular biosynthesis is correlated with theconcentration and the period of drug treatment in PLC/PRF/5 cells butthe inhibition of macromolecular biosynthesis is only correlated withthe concentration of drug treatment in KB cells.

These results indicated that compounds 16, 17 and 21 are potentantitumor agents which suppress cellular DNA, RNA and protein synthesis.

Table 3 hereinbelow summarizes the hydrogen-proton site for several ofthe compounds of the present invention. Specifically it shows thechemical shift (H-NMR (CDCl₃)) as shown in Example 9 (C₁₃ H₈ O₄). As itis known in the H-NMR technology, m=multiplet; d=doublet; t=triplet, ands=singlet.

                                      TABLE 2                                     __________________________________________________________________________    example                                                                            H-1 H-2  H-3   H-4  H-5    H-6  H-7    H-8     OH(alls)                                                                           OMe(alls)            __________________________________________________________________________    10       6.19(d)    6.36(d)                                                                            7.81(m)                                                                              7.43 7.55(m)                                                                              8.08(dd)                                                                              12.70                     13   7.46(s)        6.92(s)                                                                            7.31-7.36(m)                                                                         7.37-7.57(m)                                                                              8.13(dd)                          15   8.09(d)                                                                           7.02(d)         7.69-7.74(m)                                                                         7.57(m)                                                                            7.34-7.40(m)                                                                         8.32(dd)     4.02.4.04            17   8.22(d)                                                                           6.92(dd)   6.98(d)     7.19(dd)                                                                           7.25(dd)                                                                             7.88(dd)     3.90.4.02            18   8.03(d)                                                                           6.90(dd)   6.90(d)     7.27(dd)                                                                           7.22(dd)                                                                             7.56(dd)                          20       6.74(dd)                                                                           7.50(t)                                                                             6.95(dd)                                                                           6.74((d)    6.85(dd)                                                                             8.16(d)      3 86.3.97            21       6.77(dd)                                                                           7.66(t)                                                                             7.00(dd)                                                                           6.86(d)     6.93(dd)                                                                             8.02(d) 12.84                     23   7.66(d)  7.24(dd)                                                                            7.34(d)                                                                            6.80((d)    6.90(dd)                                                                             8.21(d)      3.89                 24   7.44(d)  7.24(dd)                                                                            7.46(d)                                                                            6.93(d)     6.88(dd)                                                                             8.01(d)                           26   8.23(d)                                                                           6.93(dd)   6.84(d)          6.93(dd)                                                                             8.23(d)      3.93                 27   7.98(d)                                                                           6.86(dd)   6.82(d)          6.86(dd)                                                                             7.98(d)                           2    8.04(d)                                                                           6.91(dd)   6.87(d)                                                                            7.82   7.43(m)                                                                            7.59(m)                                                                              8.16(dd)                          __________________________________________________________________________

What is claimed is:
 1. The method of treatment of a living subject affected by hepatoma which consists of administering to said subject by the oral route up to three times daily a pharmaceutical composition in unit dosage form containing 50-300 mgs. per dose of a compound which is a member selected from the group consisting of 3-(2,3-Epoxypropoxy)xanthone, 6-(2,3-Epoxy-propoxy)-1-hydroxyxanthone, 2,6-di(2,3-epoxypropoxy)xanthone, 3,5-di(2,3-epoxypropoxyl)-1-hydroxyxanthone and 3,4-Dihydroxy-xanthone.
 2. A pharmaceutical composition for the treatment of hepatoma in unit dosage form containing 50-300 mgs. for oral administration or 2-15 mgs. for intravenous administration of a compound which is a member selected from the group consisting of 3-(2,3-Epoxypropoxy)xanthone, 6-(2,3-Epoxypropoxy)-1-hydroxy-xanthone, 2,6-di(2,3-epoxypropoxy) xanthone, 3,5-di(2,3-epoxypropoxy)-1-hydroxyxanthone and 3,4-Dihydroxyxanthone. 